Nate Clements signals to the crowd after breaking up a fourth quarter pass in the 49ers home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

Nate Clements signals to the crowd after breaking up a fourth...

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The 49ers Nate Clements breaks up a pass for Nate Burelson in the second half of the 49ers home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

The 49ers Nate Clements breaks up a pass for Nate Burelson in the...

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Former 49ers owner Eddie DeBartolo Jr. and Jerry Rice watch as DeBartolo's plaque is unveiled during a halftime ceremony Sunday.

Photo: Brant Ward, The Chronicle

Former 49ers owner Eddie DeBartolo Jr. and Jerry Rice watch as...

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The Seahawks' Justin Forsett is brought down by the 49ers' Glen Coffee in the first half of the 49ers home opener Sunday.

Photo: Brant Ward, The Chronicle

The Seahawks' Justin Forsett is brought down by the 49ers' Glen...

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Fans go crazy as 49ers players leave the field in their home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

Fans go crazy as 49ers players leave the field in their home opener...

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Tight end Vernon Davis of the San Francisco 49ers run into the field during the home opener against the visiting Seattle Seahawks at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

Tight end Vernon Davis of the San Francisco 49ers run into the...

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Seahawks quarterback Seneca Wallace has trouble with a snap in the third quarter of the 49ers home opener Sunday.

Photo: Brant Ward, The Chronicle

Seahawks quarterback Seneca Wallace has trouble with a snap in the...

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Members of the Niner Noise Drumline waves at a pair of F-18 fighters during the pre-game ceremony between the San Francisco 49ers and visiting Seattle Seahawks at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

Members of the Niner Noise Drumline waves at a pair of F-18...

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Defensive end Ray McDonald of the San Francisco 49ers sacks quarterback Matt Hasselbeck of Seattle Seahawks during the first quarter at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

Defensive end Ray McDonald of the San Francisco 49ers sacks...

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Seahawks quarterback Seneca Wallace is grabbed from behind by Manny Lawson in the fourth quarter of the 49ers home opener Sunday.

Photo: Brant Ward, The Chronicle

Seahawks quarterback Seneca Wallace is grabbed from behind by Manny...

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A 49ers fan cheers during the home opener against the Seattle Seahawks at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

A 49ers fan cheers during the home opener against the Seattle...

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Wide receiver T.J. Houshmandzadeh (84) of the Seattle Seahawks misses a catch while being defended by defensive back Reggie Smith (31) of the San Francisco 49ers during the home opener at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

Wide receiver T.J. Houshmandzadeh (84) of the Seattle Seahawks...

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49ers head coach Mike Singletary expresses his dislike for a play in the second half of the home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

49ers head coach Mike Singletary expresses his dislike for a play...

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Frank Gore runs for his first touchdown of the game in first quarter of the 49ers home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

Frank Gore runs for his first touchdown of the game in first...

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Frank Gore goes into the crowd briefly after his second touchdown of the 49ers home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

Frank Gore goes into the crowd briefly after his second touchdown...

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Frank Gore (top) is celebrates with Vernon Davis after Gore's touchdown in the first half of the 49ers home opener against the Seattle Seahawks on Sunday.

Photo: Brant Ward, The Chronicle

Frank Gore (top) is celebrates with Vernon Davis after Gore's...

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Frank Gore is cheered by the south endzone crowd after his second touchdown of the game in the second half of the 49ers home opener against the Seattle Seahawks on Sunday.

Running back Frank Gore (21) of the San Francisco 49ers is being tackled by cornerback Ken Lucas (31) of the visiting Seattle Seahawks at Candlestick Park in San Francisco on Sunday.

Photo: Stephen Lam, The Chronicle

Running back Frank Gore (21) of the San Francisco 49ers is being...

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Former 49ers owner Eddie DeBartolo Jr. (right) and famed receiver Jerry Rice embrace as they walk from the field after a halftime ceremony. DeBartolo's two grandsons are in foreground.

Photo: Brant Ward, The Chronicle

Former 49ers owner Eddie DeBartolo Jr. (right) and famed receiver...

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Corner back Nate Clements (22) of the San Francisco 49ers, right, breaks up a pass to T.J. Houshmandzadeh (84), left, of the visiting Seattle Seahawks late in the fourth quarter at Candlestick Park in San Francisco, Calif. on Sunday, Sept. 20, 2009. The 49ers defeated the Seahawks 23-10.

Photo: Stephen Lam, The Chronicle

Corner back Nate Clements (22) of the San Francisco 49ers, right,...

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Quarterback Shaun Hill (13), center throws a pass to running back Frank Gore (21) in the fourth quarter against the Seattle Seahawks at Candlestick Park in San Francisco, Calif. on Sunday, Sept. 20, 2009. The 49ers defeated the Seahawks 23-10.

The last time the 49ers held sole possession of the NFC West lead this late in the season, it was ... well, OK, it was 2007. Never mind.

"I don't really compare years," cornerback Nate Clements said after San Francisco's 23-10 smothering of the Seattle Seahawks. "Different players, personnel, coaches ... what we are now is a team that wants to be physical, and set the tempo to the way we like it, and force the other team to play our type of football."

That's the rudimentary answer. For the poetry, it's over to linebacker Takeo Spikes.

"When we play like we have the last two weeks, it's like the quote, when you speak so loud but nobody can hear you," he said. "Right now, we're talking as loud as we can, and nobody can hear a word."

This is after two weeks of eviscerating what should be two of the NFC's best offenses in Arizona and Seattle. As of this moment, the 49ers' defense has allowed two touchdowns and four field goals in two games and 26 possessions, and though there are mitigating circumstances in both examples (neither Arizona nor Seattle can run the ball worth a damn, and Seattle was missing 10 starters by game's end Sunday), this is still a scoreboard league. You win, you talk.

Even if, as Spikes maintains, nobody can hear you.

Oh, Seattle moved the ball on occasion - four drives expired inside the 49ers' red zone, but only the second one resulted in a touchdown, a 1-yard toss from Seneca Wallace to Julius Jones.

Therein lies this team's core truth: It has not yet allowed the other team to have its way with the game. Of all Mike Singletary's proclamations about the 49ers' Ethos, it is this feature that has been most dramatically changed.

Yes, Frank Gore suddenly can run 80 yards without being winded, let alone touched, but the 49ers now hit more often, and with greater force per square foot, than they have in years. In establishing the rules of engagement early and often both in Glendale the previous week and Candlestick sur la Mer on Sunday, the defense has become the team's defining element.

"I think at the end of the day, this is just refinement of what we've been doing all year, all the way back to March," Spikes said. "Now we're coming to expect it."

That task has been made easier because the 49ers are the only team in the division that runs with any confidence at all. It was improved all the more when Patrick Willis knocked out Seattle quarterback Matt Hasselbeck late in the first half. Hasselbeck wobbled toward the sideline after a slide that took the ball to the 49ers' 1-yard line, then collapsed with an injured rib and did not return.

"I didn't know if I'd hurt him or not," Willis said. "I knew I didn't take my helmet and spear him in the back. It was straight shoulder pad.

"I feel like we're becoming more physical but it's something we've talked about all offseason, about being relentless and physical all across the board, to create an identity of who we are."

Say, like the identity of being 2-0. And like the identity of a team that finally is working to live down the "finesse" albatross that has stayed with it all these years.

"Last year, we weren't really getting these things," safety Michael Lewis said of the little things that the physical play is creating that it didn't under the previous three regimes. "But we're flying around and making plays, and things are coming to us now."

Well, coming to the other guy, more like.

We are still at the small sample-size portion of the season, but the two wins the 49ers have now are two fewer they'll need later, and there is no looking that particular gift horse down its yap. There will be other tests, and far sterner than these two.

Starting, cheerfully enough for those of you who want to see just how good the 49ers defense actually is, Sunday in Minnesota. The 49ers, who have held their first two opponents to a total of 106 yards and no touchdowns rushing, faces the Vikings' real franchise face, Adrian Peterson, who has almost three times as many yards and four more scores.

Brett Favre might try to be more Favrian than he has been in the first two games, but the Vikings are Peterson's team, plain and simple.

Thus, the result of that matchup will determine much of who the 49ers really are - or to put it in Spikes' terminology, just how loud the 49ers need to talk, and how hard it will be to hear them.